Behavioral Sciences MCAT

Phrenology

A science claiming to determine a persons personality by studying bumps on their skull, proposed by Franz Gall

Pierre Flourens

Used extirpation (removal of parts) to study and discover functions of major sections of the brain

Functionalism

How mental processes help individuals adapt to their environment

William James and John Dewey

Known for Functionalism

Paul Broca

Studied people with legions in specific regions of the brain and discovered speech production was in left hemisphere of frontal lobe

Broca’s area

An area in the frontal lobe, usually in the left hemisphere, that directs muscle movements involved in speech and controls language expression.

Hermann von Helmholtz

Physicist and physician who discovered how to measure of the speed of a nerve impulse, made psychology a science

Sir Charles Sherrington

Coined the word "synapse" to define the connection between two neurons

Sigmund Freud

Father of psychoanalytic perspective who examined the ways childhood experiences and our unconscious affect behavior

Sensory neurons

Afferent (receptors —> Spinal Cord (CNS))

Interneurons

Between other neurons, mainly in CNS

Motor neurons

Efferent (CNS —> muscles and glands)

Reflex arcs

Interneurons in spinal cord relay info to the source of stimuli while routing it to the brain

Central Nervous System

Brain and Spinal Cord (CNS)

Peripheral Nervous System

Nervous tissue and fibers outside central nervous system (PNS)

Neurotransmitters

Released by neurons to carry a signal through the synapse into another neuron

Acetylcholine

Used by somatic (body) nervous system to move muscles. Also used by parasympathetic nervous system (relaxed) and CNS

Dopamine

Maintains smooth movements and steady posture

Endorphins/Enkephalins

Natural pain killers

Epinephrine/Norepinephrine

Maintains wakefulness and mediate fight/flight responses. Epinephrine acts as a hormone and norepinephrine acts as a neurotransmitter

GABA (Gamma-Aminobutyric Acid)

Inhibitory neurotransmitters that act as brain stabilizers

Glutamate

Acts as excitatory neurotransmitter

Serotonin

Modulates mood, sleep, eating, and dreaming

Cortisol

Stress hormone released by adrenal gland cortex

Testosterone

Mediates sex drive in males. Increases aggressive behavior. Produced in gonads (ovaries/testes) and released by adrenal cortex

Estrogen

Mediates sex drive in females. Produced in gonads (ovaries/testes) and released by adrenal cortex

Hindbrain

Cerebellum, medulla oblongata, reticular formation

Cerebellum

Located at the rear of the brainstem, its functions include processing sensory input, coordinating movement output/balance, and enabling nonverbal learning and memory

Medulla Oblongata

The base of the brainstem that connects to spinal cord and controls involuntary vital functions such as reflexes, breathing, heart rate, sneezing, coughing, and swallowing

Reticular Formation

A nerve network that travels through the brainstem and thalamus and plays a role in arousal.

Midbrain

Inferior and superior colliculi

Inferior Colliculus

Sound localization, sound detection, and sound-induced behaviors

Superior Colliculus

Processes optical stimuli, orients attention, and coordinates eye and head movements

Forebrain

Thalamus, hypothalamus, basal ganglia, limbic system, cerebral cortex

Methods of Study

Electroencephalography (EEG). Regional cerebral blood flow

Thalamus

Relay station for sensory information

Hypothalamus

Homeostasis (fight/flight/feed/fornicaton)

Basal ganglia

Smooths movements and helps postural stability

Limbic system

Septal nuclei, amygdala, hippocampus

Septal nuclei

Pleasure and addiction

Amygdala

Fear and aggression

Hippocampus

Emotion and memory

Cerebral cortex

4 lobes: frontal, parietal, occipital, temporal

Frontal lobe

Executive function, impulse control, speech, motor

Parietal lobe

Touch pressure, temperature, pain, spatial processing

Occipital lobe

Visual

Temporal lobe

Sound, speech perception, memory, emotion

Left hemisphere

Logic, math, language, analytic

Right hemisphere

Intuition, creativity, spatial processing

Neural tube

Becomes the CNS

Neural crest cells

Spread out throughout the body, differentiating into many different tissues

Primitive reflexes

Exist in infants and should disappear with age

Rooting reflex

Infant turns head towards stimulus (breastfeeding)

Moro reflex

Infant extends arms in response to falling sensation

Babinski reflex

Big toe is extended and other toes fan out in response to brushing on sole of foot

Grasping reflex

Infant grabs anything put into hands

Sensory receptors

Sensory nerves that respond to stimuli

Sensory ganglia

Collection of cells bodies outside the CNS

Projection areas

areas in the brain that analyze sensory input

Absolute threshold

The minimum amount of stimulus energy that will activate a sensory system

Threshold of conscious perception

The minimum stimulus energy that will create a signal large enough in size and long enough in duration to be brought into awareness

Difference threshold

The minimum different in magnitude between two stimuli before one can perceive this difference

Weber’s Law

Just Noticeable Difference (JND) for a stimulus is proportional to the magnitude of the stimulus

Signal detection theory

Refers to the effects of nonsensory factors, such as experiences, motives, and expectations on the perception of stimuli. Accounts for response bias

Adaptation

Refers to an increase or decrease in sensitivity to a stimulus

Cornea

Gathers and filters incoming light

Iris

Controls size of pupil and is the colored part of the eye. Divides front of the eye into anterior and posterior chamber. Also contains 2 muscles: the dilator and the constrictor pupillae

Lens

refracts incoming light to focus on the retina

Aqueous humor

Produced by the ciliary body, Nourishes the eye and gives the eye its shape. Drains through the canal of Schlemm

Retina

Houses rods (black and white) and cones (color)

Pathway from retina

Rods/cones —> Bipolar cells —> Ganglion cells —> Optic nerve

Retinal disparity

Space between eyes; allows for binocular vision and depth

Sclera

White part of the eye

Parallel processing

Color, form, and motion at the same time

Magnocellular cells

Motion. High temporal (2D) resolution

Parvocellular cells

Shape. High spatial (3D) resolution

Visual pathway

Eye —> optic nerve —> optic chiasm —> optic tracts —> LGN —> visual radiations —> visual cortex

Outer ear

Pinna, external auditory canal, tympanic membrane

Middle ear

Ossicles (Malleus, Incus, Stapes)

Inner ear

Cochlea (sound), utricle and saccule (linear acceleration), and semicircular canals (rotational accleration and balance)

Malleus

Hammer

Incus

Advil

Stapes

Stirrup

Superior olive

Localizes sound

Inferior colliculus

Startle reflex

Auditory pathway

Cochlea —> vestibulocochlear nerve —> medical geniculate nucleus (MGN) —> auditory cortex

Smell

Detection of aerosolized chemicals by olfactory chemoreceptors (olfactory nerves)

Pheromones

Chemicals given off by animals that have an effect on social foraging and sexual behavior

Taste

Detection of dissolved compounds by taste buds in papillae

Somatosensation

Refers to four touch modalities: pressure, vibration, pain, temperature

Two-Point Threshold

Minimum distance necessary between 2 points of stimulation on the skin such that the points will be felt as two distinct stimuli

Physiological zero

Normal temp of skin to which objects are compare to

Nociceptors

Pain reception, Gate theory of pain

Kinesthetic sense

Proprioception, the body's ability to sense its position and movement in space